A microfilm is used as one means for storing records of many documents, prints, etc. The microfilm carries these records in a greatly reduced scale, so that the various picture image data recorded on the microfilm can be reenlarged to be projected on a screen or reenlarged to be copied by a copying apparatus when so required.
A conventional microfilm in the form of a silver-halide photosensitive member is defective in that, unlike a magnetic tape once picture image data are recorded thereon, other required picture image data cannot be additionally recorded theron or the picture image data already recorded thereon cannot be modified or corrected.
A microfilm in the form of an electrophotosensitive member permitting addition and modification or correction of recorded picture image data has been developed to obviate the defect of the conventional microfilm. This electrophotographic microfilm is formed by laminating a layer of a transparent conductive material and a layer of a transparent photoconductive insulating material on a base of a transparent insulating material. The electrophotographic microfilm has the feature of exhibiting photosensitivity when electrostatically charged. Another feature of the electrophotographic microfilm is that it requires a short length of time and a narrow space for developing. Such an electrophotographic film having the features above described, therefore, after recording a plurality of picture image data of different themes in spaced-apart relation on the electrophotographic microfilm, relevant picture image data can be additionally recorded adjacent to the record picture image data as required.
Recording of picture image data on such an electrophotographic microfilm requires electrophotographic processing means for performing the various steps of processing including electrostatic charging, exposure, developing and fixing of picture image data to be recorded on the electrophotographic microfilm. Also, reading of picture image data recorded on the electrophotographic microfilm requires means for enlarging and projecting the picture image data recorded on the electrophotographic microfilm. For this purpose, an electrophotographic camera processor-reader has been developed which is provided with both the electrophotographic processing means and the enlarging-projecting means described above.
FIG. 1 shows schematically the structure of one form of a prior art electrophotographic camera processor-reader. Referring to FIG.1, an electrophotographic microfilm 101 in web or belt form is wound at both ends thereof around a pair of winding shafts 102 respectively, and these winding shafts 102 are supported so as to rotate in both normal or reverse directions relative to a housing 103. An original-supporting glass plate 105, on which an original 104 is placed with its front side facing downward, is disposed onthe upper part of the housing 103, and a light source or lamp 106 illuminating the original 104 is disposed beneath the original-supporting glass plate 105.
Along the electrophotographic micrograph 101 extending between the pair of winding shafts 102, a charger 107, a recording lens 108, a developer 109, and a fixing and projecting lamp 110 are disposed in the above order. The charger 107 acts to electrostatically charge the electrphotographic microfilm 101 to render the charged area photosensitive, and the recording lens 108 acts to focus picture image data carried by the original 104 onto the charged area of the electrophotographic microfilm 101. The developer 109 acts to toner-develop an electrostatic latent image of the picture image data formed on the electrophotographic microfilm 101, and the lamp 110 has the function of heat-fixing the toner image of the picture image data formed by the developer 109 on the electrophotographic microfilm 101 and functions also as an illumination light source for projection of an enlarged toner image with transmitted light. For this purpose, a heat-shielding filter111is movably interposed between the electrophotographic microfilm 101 and the lamp 110 so that it can be brought to a non-heat-shielding position during the step of fixing and to a heat-shielding position during the step of projection. A projection lens 112 is disposed opposite the illuminating lamp 110 on the other side of the electrophotographic microfilm 101, so that the toner image formed on the electrophotographic microfilm 101 can be projected through three reflecting mirrors 113 onto a translucentscreen 114 as an enlarged image.
The prior art electrophotographic camera processor-reader having such a construction is defective in that the overall apparatus tends to become large in size and quite expensive because of the fact that the optical systems for picture image data recording and projecting purposes are provided independently of each other.
On the other hand, U.S. Pat. Nos. 4,286,864 and 3,697,176 disclose an apparatus having both the function of a camera processor and the function of a reader. Both of these U.S. patents have, however, been defective in that the necessity for the provision of a movable mirror for changing over the optical path results inevitably in a bulky overall apparatus, because a projection screen and an original-supporting glass plate are disposed at separate positions in each of them. In U.S. Pat. No. 3,781,106 in which an original-supporting plate acts also as a projection screen, the arrangement is such that light emitted from a projection light source and reflected from a recorded film is projected onto the screen. Thus, when the idea disclosed in this U.S. Pat. No. 3,781,106 is applied to an electrophotographic apparatus using a transparent electrophotographic film, the light reflected from a recorded film is projected onto a screen through an optical system including a lens, a reflecting mirror and the like. Such an apparatus requires a lamp emitting light of high luminous intensity compared with an apparatus of the type in which light transmitted through a film is projected onto a screen. Such an apparatus is therefore disadvantageous from the aspects of cost and space. Also, U.S. Pat. No. 3,781,106 does not disclose any arrangement permitting utilization of transmitted light in view of the relation between the light source and other members but merely resorts to utilization of reflected light. Further, none of the three U.S. patents cited above moves a fixed mirror in a non-operating state of the apparatus, thereby making the overall apparatus more compact and less bulky.